Mold and method of casting steel ingots



Feb 19 1924. v 1,4s4,1 12

R. G. coATEs MOLD AND METHOD OF CASTING STEEL INGOTS Filed Oct. 18, 1920 lllllll '15 ing steel ingots Patented Feb. 19, 192

RAY G. COATES,

FHQQE.

OF PASADENA, CALIFORNIA, ASSIGNOR '10 VALLEY MO'ULD AND IRON MOLD AND METHOD or ASTING srnEL Neo'rs.

Application filed October 18, 1920. SerialNo. 417,543.

To all whom it may concern:

Be it known that I, RAY G. CoA'rEs, a citizen of the United States, and a resident of the city of Pasadena, in the county of Los Angeles, State of California, have invented new and useful Improvements in Molds and Methods of Casting Steel Ingots, of which the following is a specification.

This invention relates broadly to metal lurgy and more specially to a process and mold for casting steel ingots.

The principal object of the present invention is the process and mold for castwherein the mold is a chill mold arranged substantially horizontal with the axis thereof inclined slightly to horizontal.

Another object of the present invention 1s the method and mold for casting steel in gots wherein the top surface of the matrix portion of the mold is inclined slightly to the horizontal with a gas outlet at the highest portion thereof.

A further object of the present invention is a horizontal chill mold for casting chill ingots wherein the top surface of the matrix portion of the mold is inclined slightly to the horizontal in such manner that the surface 39 of the molten steel in the mold gradually advances from one end of the said matrix top surface to the other end thereof and with a gas outlet in the mold adjacent the highest portion of said matrix surface thereof.

A still further object of the present invention is the process of casting steel ingots in a covered chill mold wherein the top surface of the matrix of the mold is inclined slightly to the horizontal in such manner that molten steel in the mold tends to gradually mold gases through a gas escape opening i the highest portion of. the mold.

More specifically, an object of the present invention comprises casting a steel ingot in a substantially horizontal ingot covered chill mold with a runner at one end of the mold and a gas outlet at the other end thereof and with the top surface of the mold inclined slightly from.the .runner toward the gas outlet.

Other and further objects of the present invention will in part be obvious and will in part be pointed out hereinafter b referonce to the mpanying drawings orming expel apart of this application and wherein like parts are represented by like characters throughout the several figures thereof.

Realizing that the presentinvention may be carried out by manipulations and in constructions other than those specifically herein disclosed it is desired the disclosure herewith shall be considered as illustrative and not in the limiting sense. I

Figure 1 is a more or less diagrammatic longitudinal section through a mold embodying the present invention;

Figure 2 is a detail view of one end of the mold according to the present invention and illustrating the manner of expulsion of gases from the mold in carrying out the present invention.

Figure 3 is a sectional view taken on line 33 of Figure 2.

In the art of casting steel ingots in horizontal molds with chill covers thereon it appears gases to trap adjacent the skin of the ingot and particularly adjacent the top of the ingot. This is due to the fact that the mold at the beginning of the teeming operation is filled with air and also the fact that the molten steel contains occluded gases which are partly ex elled from the steel as the steel solidifies in t e mold. In the ordina horizontal mold with the axis thereof horizontal the steel gradually fills the mold and the mold gases rise-into the space between the top of the molten steel and the cover for the'mold. As the mold fills, the steel comes against the entire chill cover with a final slap which immediately chills and forms a chilled metal skin which traps the mold gases. When this occurs subcutaneous cavities form beneath this cold skin. These cavities o-rdinarily'do not tend to fill because the gas bubbles prevent molten steel from touching the chilled metal and the solidified that there is a tendency for moldmetal therefore cannot build up back of the bubbles, and the result thereof is a line of bubbles which grow in length longitudinally from the chilled wall, or skin. The direction of movement of the molten metal under ordinary conditions is substantially vertical, during the filling of a horizontal mold, so that when the mold is finall filled and the vertical movement is stoppe there is-no movement of metal tending to sweep these bubbles from their original initial positions. Furthermore, there appears to be a liability of entrapping, in the molten steel, air which was originally in the mold when the pouring began. These entrapped air bubbles sometimes are deep seated in the ingot and at other times appear closely beneath the original chilled skin. The various gas cavities in the ingot are liable to be detrimental to the final product where these cavities are located near the surface of the ingot because in. rolling such cavities are liable to break out, thereby permitting oxida-' tion of the cavity surfaces, which tends to prevent the surfaces from welding, thus causing cold shuts or other defects in the finished product. The defects are not very great where the bubbles are deep seated in the ingot because such cavities tend to weld shut on rolling the ingot.

The present invention overcomes the difiiculties of the known art by providing for the casting of a horizontal smooth ingot in such manner as to expel mold gases during the pouring operation. This may be accom-- plished by arranging the mold with the axis thereof substantially horizontal but with the upper surface of the mold matrix inclined slightly to'the horizontal and with the gas outlet adjacent the higher part of the inclined surface. Under these conditions, where the teeming operation is carried on slowly, the molten steel gradually fills the mold until the mold is nearly fullfAs the surface of the molten steel approaches the cover of the mold, the mold gases will be gradually driven into the s ace between the surface ofthe molten stee and the cover, and as the steel fills this space the gases are compressed and thus driven out of the mold through the gas-escape opening provided for that purpose. As the mold gradually fills the steel surface being horizontal contacts at one end with the cover and leaves a wedge shaped space between the cover and the surface of the steel with the gas escape opening adjacent the base of the Wedge. As the teeming operation is carried on further the.

molten steel surface gradually rises and the line of contact of the surface and the cover gradually approaches the gas outlet since i into the graduall the wedge space is gradually decreased. This operation tends to drive the mold gases ahead of the enclosing chilled surfaces and causes these gases to travel in the direction of movement of the molten steel. This direction of movement of the molten steel tend to loosen or sweep off mold gases which start to collect against the cooling metal or chilled wall. The result is that the gases are swept decreasing wedge-shaped area and are gra ually expelled through the gas opening so that when the mold is finally filled the ingot becomes substantially solid metal with all mold gases having been swept through the gas escape opening.

The present invention may be embodied made.

means structions disclosed in the drawings here- 7 with are to be considered, as more or less diagrammatic. As illustrated the mold may comprise a body portion 1' which may be provided with suitable supporting legs 2 and 4: and is formed with a mold cavity 5 of the desired shape for the ingot to be Preferably the side walls of the body portion are substantially uniform in thickness and one of the legs, for example leg 2, is higher than the leg 4. This different height inthe supports inclines the body portion slightly to the horizontal. Preferably the mold is capped with a suitable chill cover 6 which may be provided with lifting staples land with a slotted opening 8 to receive a runner 9. This runner may comprise a fire-clay tube having an opening which leads from a fountain 10 into the mold cavity 5. The opposite end of the cover may also be provided with a slotted opening 11 through which extends a gas escape tube or conduit 12 that likewise is formed of fire clay or other suitable material. The opening in the gas escape member 12 leads to the upper portion of the mold cavity adjacent the cover so that this gas escape is located substantially in the highest part of the mold matrix space.

By referring to Figure 2 it will be noted that as the mold is gradually filled with molten steel the steel surface rises along the inner surface of the cover thereby providing a wedge-shaped air space 13 into which mold gases are forced and from which the gases escape through the gas opening. 12, as indicated by arrows A. This construction and method results in the production of an ingot which is formed" with smooth surfaces, and which is adaptable for rolling without cropping and wherein the metal is substantially free from bubbles or pipes.

Having thus described my invention, what ll claim is:

1. The method of casting steel ingots in horizontal cover chill molds which com prises arranging the upper surface of the matrix of the mold at a slight incline to the horizontal maintaining said. incline constant during the pouring operation and gradually filling the mold at the low end thereof in such manner as to expel mold gases from the highest portion of the mold cavity at the end opposite to the introduction of the molten steel.

2. The method of casting chilled ingots steel or the like which comprises casting the ingots in covered chill molds with the axes of the ingot substantially horizontal and with the top surface of the mold matrix inmatrix portion of the mold during the final filling of the mold, maintainin the angle at thepoint of said wedge-shape space constant during pouring and gradually decreasing said wedge-shaped space to drive out the gases at the high end of the mold cavity by filling the mold cavity with molten metal introduced at the lower end thereof.

3. The method of casting chilled ingots steel or the like which comprises casting the ingots in covered chill molds with the axes of the ingot substantially horizontal and with the top surface of the mold matrix inclined slightly so that the molten metal meets the top under surface of said matrix portion at an acute angle to form a wedgeshaped space between the top surface of the molten steel and under top surface of the matrix portion of the mold during the final filling of the mold, maintaining constant the angles of said wedge-shaped space during pouring, and gradually decreasing said wedge-shaped space in a direction away from the incoming molten steel end of the mold while maintaining said acute angle substantially constant b filling the mold cavity with molten meta introduced at the low end thereof.

4. The method of casting steel ingots or the like in covered chill molds which comprises introducing the molten steel at the low end, thereby causing general movement of metal in the mold during teeming to have a direction fromthe low end of the mold toward the high end thereof and providing that the direction of movement of contact between the molten metal surface and the angle between the surface of the metal and the final top surface of the matrix of the mold during teeming.

5. The method of casting steel in ots or the like in covered chill molds whic comprises introducing the molten steel at the low end thereby causing general movement of metal in the mold during teeming to have a direction from the low end of the mold toward the high end thereof and providing that the direction of movement of contact between the molten metal surface and the final top surface of the mold matrix shall be in the same general direction as the movement of the meta-l, permitting mold gases to escape from a portion of themold toward which the molten metal is moving, causing the. surface area of the molten steel'to gradually diminish until the area is substantially zero when the mold is filled, and maintaining the angle between the surface of the molten metal and the final top surface of the matrix of the mold a constant angle during the teeming operation.

6. As an article of maufacture, a horizontal mold for steel ingots and the like comprising a chill body portion having a mold cavity therein. a chill cover adapted to fit on said body portion. and a gas outlet leading from the highest part of said mold cavity, an inlet conduit leading to the low end of the mold at the opposite end to the gas outlet with the top surface of the enclosed mold cavity being permanently slightly inclined upwardly from the horizontal whereby the surface of the molten steel contacting with said top surface during pouring will move from the low end toward said gas outlet and to provide a fixed angle between the surface of the molten steel and the top of the mold cavity during such movement.

7. A horizontal mold for casting steel ingots and the like comprising a stationary Clllll body portion having a trough-shaped matrix formed therein, a chill cover for said body with its under surface slightly inclined from the horizontal. an inlet conduit set in the low end of the matrix, and a gas outlet conduit extending from the highest part of the matrix at the end opposite to the inlet conduit.

RAY G. COATES. 

